Convert from a parent style doctype?

First thanx for a very nice lite package, should realy be in the next version of Umbraco.

One question, I have today a site where we have a structure like this on our doctypes.

PageBase- 2col-- NewsPage-3col--HomePage--GenericPage

On the PageBase doctype we have a SEO, Generic tab with propertiesAnd on the 2col and 3col we have widget tabs handling 2 or 3 columns of content.

The other pages only have the properties that are specific for them, now the problem.

This would be great to have mixins like SEO, Generic, Widget and flatten the structure of our doctypes, but how can I convert this without loosing data on the pages and then also move the doctypes from their parents?

Other than that, there isn't a great deal you can do with an existing structure, as documents aren't meant to allow swapping of their doc types. That said, there is nothing to stop you using DocType mixins in combination with inherited doc types.

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